Some items are missing from the creative inventory, specifically the new ones from the latest update. These items are impossible to get. Using commands won't work, searching in the creative menu doesn't work, and closing and re-opening the world won't work. As can be seen in the image, the creative inventory is messed up, and is not how it is supposed to be. In the second image, I tried using commands, but it doesn't recognise elytra. Some other missing items in this world are fireworks, stained glass armour stands and others. When typing "/give @p elytra", before pressing enter, the item shows up on the chat recognising the item, but then does not recognise it upon hitting enter. I know not of how to reproduce this. This also happened to me on my android.